Reversion control device for watercraft exhaust system

ABSTRACT

The present invention is a reversion control device including a housing with a proximal end and a distal end. The reversion control device further includes at least one reversion cone, a stationary vane and a flapper. In one example, the reversion control device includes an oxygen sensor for monitoring the oxygen content of the engine for routine operations or for diagnostic purposes. In an example, the housing includes an expansion chamber to house the reversion cone, the stationary vane and the flapper. In another example, the stationary vane is housed within the reversion cone. In yet another example, the reversion control device is integrated within an exhaust manifold elbow.

This application is a continuation-in-part of application Ser. No.11/401,627, filed Apr. 10, 2006.

FIELD

The field of the present invention relates generally to watercraftexhaust systems. More particularly, the present invention relates to adevice attached to the exhaust system for controlling water reversionback to the engine.

BACKGROUND

In a typical motorized watercraft, the exhaust system includes anexhaust manifold elbow. The exhaust manifold elbow includes an exhaustgas passage and a water passage with the two passages juxtaposed.Exhaust gas from the engine exits the exhaust system through the exhaustgas passage. Water from the lake or ocean, injected into the exhaustsystem for cooling the running engine, passes near the exhaust gaspassage, where it further cools the exhaust gas. The exhaust gas andcooling water exit the elbow mixing area of the exhaust manifold elbowand are mixed with each other. Ideally, both are then expelled.

In motorized watercraft, portions of the exhaust system can be immersedin the water (e.g., lake or ocean) while the engine is running. Thisarrangement may cause water to move back towards the engine through thegas passage. This is known as water reversion. Water reversion isundesirable for many reasons. Water in the engine may damage it. Waterreversion may also decrease engine performance and increase fuelconsumption since water moving upstream through the gas passage impedesthe flow of exhaust exiting from the engine. In addition, reversion ofcooling water may also occur to cause the above-mentioned problems, evenin exhaust systems where the exhaust ejection point is not immersed inwater so long as the system uses water for cooling the engine and/orexhaust gas.

Watercraft exhaust manufacturers have attempted several solutions to theproblem of water reversion, such as placing a stationary,semi-perforated cap-like structure or a stationary plate in the exhaustmanifold elbow area. While these attempted solutions may prevent someamount of water backflow, they also have the tendency to impede the flowof exhaust gas out of the exhaust system. Impeding exhaust gas flowdecreases performance and increases fuel consumption.

Accordingly, it would be desirable to provide a device for controllingwater reversion without decreasing engine performance or increasing fuelconsumption.

SUMMARY

According to one aspect, the present invention provides a reversioncontrol device comprising a housing with a proximal end and a distalend; a first reversion cone housed in the housing; and a flapper housedin the housing. In one embodiment, the reversion control device furthercomprises a stationary vane housed in the housing. In anotherembodiment, the reversion control device further comprises a secondreversion cone housed in the housing.

According to another aspect, the present invention provides a reversioncontrol device comprising a housing with a proximal end, a distal endand an expansion chamber, a first reversion cone housed within theexpansion chamber near the distal end; a stationary vane housed withinthe expansion chamber near the distal end; and a flapper housed withinthe expansion chamber near the proximal end. In one embodiment, thereversion control device further comprises a second reversion conehoused near the proximal end.

According to another aspect, the present invention provides an exhaustsystem for controlling water reversion comprising a reversion controldevice comprising a housing with a proximal end, a distal end, and anexpansion chamber between the proximal end and the distal end; a firstreversion cone housed within the expansion chamber; a stationary vanehoused within the expansion chamber; and a flapper housed within theexpansion chamber; at least one exhaust mixture hose support attached tothe reversion control device on the housing; and an exhaust mixture hosecoupled to at least one exhaust mixture hose support, the exhaustmixture hose surrounding the reversion control device. In oneembodiment, the reversion control device further comprises a secondreversion cone housed within the expansion chamber.

According to another aspect, the present invention provides an exhaustmanifold elbow comprising a reversion control device housed within theexhaust manifold elbow, the reversion control device comprising aproximal end, a distal end, a first reversion cone housed near thedistal end, a stationary vane housed near the distal end, and a flapperhoused near the proximal end. In one embodiment, the reversion controldevice further comprises a diffuser edge housed near the distal end. Inanother embodiment, the reversion control device further comprises asecond reversion cone housed near the proximal end.

According to another aspect, the present invention provides an exhaustmanifold elbow comprising a reversion control device housed within theexhaust manifold elbow, the reversion control device comprising aproximal end, a distal end, an expansion chamber between the distal endand the proximal end, a first reversion cone housed within the expansionchamber, a stationary vane housed within the expansion chamber, aflapper housed within the expansion chamber, and a second reversion conehoused in the proximal direction of the exhaust manifold elbow.

Other embodiments will be readily apparent to those skilled in the artfrom the following detailed description, wherein various embodiments areshown and described by way of illustration. The drawings and detaileddescription are to be regarded as illustrative in nature and not asrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a shows the reversion control device next to an exhaust manifoldelbow.

FIG. 1 b shows another embodiment of the reversion control device.

FIG. 2 a is a side view of an exhaust manifold elbow.

FIG. 2 b is the bottom view of the exhaust manifold elbow shown in FIG.2 a.

FIGS. 2 c and 2 d are the side view and bottom view, respectively, of analternatively shaped exhaust manifold elbow.

FIGS. 2 e and 2 f are the side view and bottom view, respectively, ofyet another alternatively shaped exhaust manifold elbow.

FIG. 3 a is a front view of the stationary vane.

FIG. 3 b shows the blades of the stationary vane.

FIG. 4 a shows the flapper as seen from the distal end.

FIG. 4 b shows the side view of the flapper in FIG. 4 a.

FIG. 4 c shows the flapper as seen from the proximal end.

FIG. 4 d shows the flapper in a closed position.

FIG. 4 e shows the distal end of the reversion control device with theflapper mounted.

FIG. 4 f shows the flapper in an open position.

FIG. 5 a shows the reversion control device mounted to the exhaustmanifold elbow at the elbow mixing area.

FIG. 5 b shows a circularly shaped exhaust mixture hose support 108.

FIG. 6 shows the circumference of one embodiment of the proximal end ofthe housing.

FIG. 7 a shows a second embodiment of the housing.

FIG. 7 b shows a third embodiment of the housing.

FIG. 8 a shows another embodiment of the reversion control device with areversion cone.

FIG. 8 b shows a reversion control device with two reversion cones.

FIG. 9 a shows a side view of the reversion cone 180.

FIG. 9 b shows a top view of the reversion cone 180.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various embodiments of thepresent invention and is not intended to represent the only embodimentsin which the present invention may be practiced. Each embodimentdescribed in this disclosure is provided merely as an example orillustration of the present invention, and should not necessarily beconstrued as preferred or advantageous over other embodiments. Thedetailed description includes specific details for the purpose ofproviding a thorough understanding of the present invention. It will beapparent to those skilled in the art, however, that the presentinvention may be practiced without these specific details.

The present invention discloses a reversion control device 100. FIG. 1 ashows the reversion control device 100 next to an exhaust manifold elbow200. The reversion control device includes a housing 110 for astationary vane 120 near the proximal end 101 and a flapper 130 near thedistal end 102. The proximal end 101 is the portion of the reversioncontrol device 100 that connects with the exhaust manifold elbow 200.The distal end 102 is the exit portion of the reversion control device100 distal from the exhaust manifold elbow 200. Within the reversioncontrol device 100, the stationary vane 120 organizes the exhaust gasflow, which increases fuel economy, while the flapper 130 at its closedposition minimizes water reversion, and hence, minimizes degradation inengine performance or engine damage. It has also been observed that theflapper 130 can increase the back pressure of the engine, allowingbetter control of the engine's torque curve. During the emission ofexhaust gas, the flapper 130 is at its open position. In the event ofback pulsing by the engine, which can cause a suction, the flapper 130flips to its closed position to minimize water reversion. In oneembodiment, a flapper stop pin 136 limits the pivoting action of theflapper 130 along pivot point 133. The reversion control device 100 addsadditional length to the typical exhaust outlet of the exhaust manifoldelbow 200. The additional extension in length provided by the reversioncontrol device 100 moves the mixture point of the exhaust gas andcooling water further away from the engine. An exhaust mixture hose 105(not shown) surrounds the reversion control device 100 and connects tothe exhaust manifold elbow 200 at the proximal end 101. FIG. 1 b showsanother embodiment of the present invention where the reversion controldevice 100 includes a reversion cone 180, a diffuser edge 170 at thedistal end 102, and an exhaust mixture hose support 108 mounted tohousing 110.

FIG. 2 a is a side view of an exhaust manifold elbow 200. The exhaustmanifold elbow 200 includes an elbow mixing area 210 which connects tothe reversion control device 100. FIG. 2 b shows the bottom view of theexhaust manifold elbow 200. The exhaust manifold elbow 200 includescooling water passage 230 and an exhaust gas passage 220.

Exhaust manifold elbows can be shaped differently than what is showed inFIGS. 2 a and 2 b. For example, FIGS. 2 c and 2 d show an alternativelyshaped exhaust manifold elbow while FIGS. 2 e and 2 f show yet anotheralternatively shaped exhaust manifold elbow. One skilled in the artwould understand that the reversion control device 100 can adapt to amultitude of exhaust manifold elbow shapes, not limited to the examplesshown here.

FIG. 3 a is a front view of the stationary vane 120. In the embodimentdepicted, the stationary vane 120 includes four stationary blades 122.One skilled in the art would understand that the quantity of blades isnot limited to four. The number of blades is a design choice andtypically ranges from two to eight blades. In one embodiment, holes 121are included for exiting water. FIG. 3 b shows the blades 122 of thestationary vane 120. Although the blades 122 are shown as slightly “D”shaped, one skilled in the art would understand that the shape of theblades 122 may vary as a design choice. In one embodiment, the blades122 each tilt at an angle φ (phi) relative to an imaginary verticalplane 123 within the housing 110 as shown in FIG. 3 b. Typical tiltangles can range from 20 degree to 60 degree relative to the verticalplane 123. In one embodiment, the stationary blades 122 each tilt at anangle of about 35 degrees relative to an imaginary vertical plane 123within the housing 110. One skilled in the art would understand thatother degrees of tilt may be possible depending on the design choice.

FIG. 4 a shows the flapper 130 as seen from the distal end. The flapper130 includes a hinge tube 131. A rod 132 (shown in FIG. 4 d) is insertedinto the hinge tube 131 at the pivot point 133 on the housing (shown inFIG. 1 a) to allow the flapper 130 to open and to close. FIG. 4 b is theside view of the flapper 130 and shows the location of the hinge tube131 relative to the vertical height of the face 135 of the flapper 130.Typically, the hinge tube 131 is located on the top half of the face135. However, one skilled in the art would understand that the locationof the hinge tube 131 is a design choice and may depend on the angle atwhich the flapper is mounted to the housing 110. In one embodiment, thehinge tube 131 is an integral part of the face 135. In anotherembodiment, the hinge tube 131 is a separate piece secured to the face135 through conventional techniques such as, but not limited, towelding. Yet other embodiments that will be readily apparent to oneskilled in the art could have hinging mechanisms that do not require atube and a separate rod.

FIG. 4 c shows the flapper 130 as seen from the proximal end 102. FIG. 4d shows the flapper in a closed position within the housing 110, andFIG. 4 f shows the flapper in an open position within the housing 110.In one embodiment, the flapper is mounted to the housing 110 at an angleΘ (theta) of about 30 degrees as shown in FIG. 4 e. A typical range ofthe angle Θ (theta) is about 20 to 60 degrees. One skilled in the artwould understand that angles outside this typical range are possiblewithout substantially diminishing the effectiveness of the presentinvention. The reversion control device 100 is mounted to the exhaustmanifold elbow 200 at the elbow mixing area 210 as shown in FIG. 5 a. Asshown in FIG. 5 a, exhaust mixture hose supports 108 are mounted tohousing 110 to keep the reversion control device 100 centered inside theexhaust mixture hose 105. In one embodiment, the exhaust mixture hosesupports 108 are in a “V” shape. FIG. 5 b shows a circularly shapedexhaust mixture hose support 108. One skilled in the art wouldunderstand that other shapes for the exhaust mixture hose supports 108may be used as a design choice. In one embodiment, a clamp is placedaround the exhaust mixture hose 105 at the location of the exhaustmixture hose supports 108 to further secure the reversion control device100.

In one embodiment, the attachment of the reversion control device 100 tothe elbow mixing area 210 is by press fitting the proximal end 101 ofthe housing 110 into the elbow mixing area 210 and then further securingthe connection with a clamp, usually over the exhaust mixture hose 105.One skilled in the art would understand that other types of fastenersmay also be used.

In one embodiment, proximal end 101 has a circumference that issubstantially circular for fitting into the elbow mixing area 210. Inanother embodiment, the proximal end 101 has a circumference that ispartially circular, with a flat portion as shown in FIG. 6. Thecircumferential shape of the proximal end 101 can vary as needed to fitthe shape of the elbow mixing area 210. The circumferential shape of theproximal end 101 can include, but is not limited to, square shape,rectangular shape, triangular shape and any polygon shape necessary tofit the circumferential shape of the elbow mixing area 210.

In one embodiment, the housing 110 is a circular tube with one of avariety of shapes for its proximal end 101 to ensure appropriate fittinginto the elbow mixing area 210. In two other embodiments, the housing110 includes an expansion chamber 112 to house the stationary vane 120and the flapper 130 as shown in FIGS. 7 a and 7 b. The transition fromthe proximal end 101 or the distal end 102 to the expansion chamber 112can be a substantially straight linear transition as shown in FIG. 7 bor a substantially curved transition as shown in FIG. 7 a. In oneembodiment, the ratio between the diameter d₁ of the distal end to thediameter d₂ of the expansion chamber is 1.5 times The ratio between thediameter d₁ of the distal end to the diameter d₂ of the expansionchamber can range from about 1.5 to 3 times One skilled in the art wouldunderstand that other ratios between and beyond the two diameters d₁ andd₂ are possible based on design choices.

In the embodiments shown in FIGS. 7 a and 7 b, the proximal end 101 canbe a variety of shapes to insure appropriate fitting into the elbowmixing area 210. It is a feature of the embodiments referred to abovethat the proximal end 101 fits into the elbow mixing area 210. Oneskilled in the art, however, would understand that, in otherembodiments, the elbow mixing area 210 may fit into the proximal end101. Additionally, in an alternative embodiment, the reversion controldevice 100 fits within the elbow mixing area 210.

In one embodiment, the length L of the housing 110 (shown in FIG. 1 a)is about 8 inches while the diameter D of the housing 110 is about 3inches. One skilled in the art would understand that the dimensions ofthe housing are not limited to this one embodiment and can varyaccording to the design choice with the limitation that the length L isalways greater than the diameter D by at least two-fold.

In one embodiment, the flapper 130 is made of titanium. Otherembodiments of the flapper 130 could be made of ceramic, stainless steelor carbon fiber. In one embodiment, the stationary vane 120 is made ofstainless steel. Other embodiments of the stationary vane 120 could bemade of titanium, carbon fiber or ceramic. In one embodiment, thehousing 110 is made of stainless steel or a steel alloy. In anotherembodiment, the housing 110 is made of titanium. One skilled in the artwould understand that the housing 110 can be made of other materialswithout affecting the effectiveness of the present invention. Materialchoices for the housing 110 are limited by the material's tolerance toendure the maximum exhaust gas temperature (typically at 1400 degreesFahrenheit) and to endure the corrosive environment of the mixture ofexhaust gas and cooling water.

In one embodiment, the flapper 130 and the housing 110 are made of thesame material. In another embodiment, the stationary vane 120 and thehousing 110 are made of the same material. In another embodiment, theflapper 130, the stationary vane 120 and the housing 110 are all made ofthe same material. In yet another embodiment, the flapper 130, thestationary vane 120 and the housing 110 are each made of a differentmaterial.

It is not essential to the present invention that the stationary vane120 be proximal to the flapper 130 or that the flapper 130 be near thedistal end of the device. In an alternative embodiment, the stationaryvane 120 is located distal to the flapper 130 with the flapper 130located near the distal end. In yet another embodiment, the flapper 130,which is located distal to the stationary vane 120, is located in anapproximate middle location between the proximal end and the distal end.It will be appreciated by those skilled in the art that the relativepositions of the vane 120 and the flapper 130 can be altered withoutdeparting from the scope of the present invention.

It is not essential to the present invention that the reversion controldevice be separate or separable from the exhaust manifold elbow. It willbe appreciated by those skilled in the art that, in yet anotherembodiment of the present invention, the distal portion of the exhaustmanifold elbow 200 may comprise the housing 110 for the stationary vane120 such that the stationary vane 120, or a portion of it, lies withinthe distal portion of the exhaust manifold elbow. In yet anotherembodiment of the present invention, the distal portion of the exhaustmanifold elbow may comprise the housing 110 for the stationary vane 120and the flapper 130 such that the stationary vane 120 lies within thedistal portion of the exhaust manifold elbow as does the flapper 130, ora portion of it.

In another embodiment, the reversion control device 100 includes areversion cone 180 as shown in FIG. 8 a. The reversion cone 180 preventswater from migrating back to the engine along the wall surface ofhousing 110. As shown in FIG. 8 a, the reversion cone 180 is mountednear the distal end 102 and fits within housing 110. In one embodiment,the reversion cone 180 is located approximately 0.75 to 1 inch from thedistal end 102. One skilled in the art would understand that thelocation of the reversion cone within housing 110 may vary withoutimpacting performance. As an example, the location of the reversion cone180 may range from 0.250 to 3.5 inches away from the distal end 102without significant impact to performance. Another embodiment is areversion control device 100 which includes two reversion cones 180, onenear the distal end 102 and one near the proximal end 101, shown in FIG.8 b. One skilled in the art would understand that the quantity ofreversion cones is not limited to two. In another embodiment, more thantwo reversion cones 180 may be included in the reversion control device100.

FIGS. 8 a and 8 b also show a threaded hole 190 for mounting an oxygensensor 192. In one embodiment, an oxygen sensor 192 is included in thereversion control device 100. The oxygen sensor 192 can be used tomonitor the oxygen content of the engine for routine operations or fordiagnostic purposes.

FIG. 9 a shows a side view of the reversion cone 180. The reversion cone180 includes a cone proximal end 181 and a cone distal end 182. As shownin FIG. 8 a, the stationary vane 120 is mounted near the cone proximalend 181. One skilled in the art would understand that the location formounting the stationary vane 120 is a design choice. In one embodiment,the stationary vane 120 is mounted closer to the cone distal end 182while in another embodiment, the stationary vane 120 is mounted proximalto the reversion cone 180.

As shown in FIG. 9 a, the cone distal end 182 includes a distal edge 183which curves toward an imaginary center axis 185 of the reversion cone180. FIG. 9 b shows a top view of the reversion cone 180. One skilled inthe art would understand that the curvature of the distal edge 183 is adesign choice. Typical range for the curvature of the distal edge 183 is45 degrees. In an alternative embodiment, the distal edge 183 isstraight and tilts toward the imaginary center axis 185.

In yet another embodiment, the reversion control device 100 includes adiffuser edge 170 at the distal end 102. The diffuser edge 170 flaresoutwardly from the center of the reversion control device 100 to deflectwater away from the exhaust gas exit passage.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention.

1. A reversion control device comprising: a housing with a proximal endand a distal end; a first reversion cone housed in the housing; and aflapper housed in the housing.
 2. The reversion control device of claim1 further comprising a stationary vane housed in the housing.
 3. Thereversion control device of claim 1, wherein the first reversion cone ishoused near the distal end of the housing.
 4. The reversion controldevice of claim 3, wherein the stationary vane is housed within thefirst reversion cone.
 5. The reversion control device of claim 1,wherein the first reversion cone includes a distal edge that issubstantially curved.
 6. The reversion control device of claim 1,wherein the first reversion cone includes a distal edge that issubstantially straight.
 7. The reversion control device of claim 1,wherein the stationary vane is housed distal to the flapper.
 8. Thereversion control device of claim 1, wherein the stationary vane ishoused proximal to the flapper.
 9. The reversion control device of claim1 further comprising a diffuser edge at the distal end.
 10. Thereversion control device of claim 1, wherein a portion of an exhaustmanifold elbow comprises the housing.
 11. The reversion control deviceof claim 1, wherein the reversion control device is connected to anexhaust manifold elbow at the proximal end.
 12. The reversion controldevice of claim 1, wherein the reversion control device includes asecond reversion cone housed in the housing.
 13. The reversion controldevice of claim 12 wherein the first reversion cone is housed at thedistal end and the second reversion cone is housed at the proximal end.14. The reversion control device of claim 11, wherein the exhaustmanifold elbow includes an exhaust gas passage for exiting exhaust gas,a water passage for exiting water and an elbow mixing area forconnecting to the proximal end.
 15. The reversion control device ofclaim 14, wherein the proximal end fits into the elbow mixing area. 16.The reversion control device of claim 14, wherein the elbow mixing areafits into the proximal end.
 17. The reversion control device of claim 1,wherein the stationary vane comprises a plurality of stationary bladeswith each stationary blade comprising a slightly D shape.
 18. Thereversion control device of claim 17, wherein each of the plurality ofstationary blades tilts at an angle of about 45 degrees relative to avertical plane within the housing.
 19. The reversion control device ofclaim 1, wherein the housing includes a pivot point; and the flapperincludes a hinge tube wherein a rod is inserted into the hinge tube atthe pivot point to pivot the flapper from an open position to a closedposition or from a closed position to an open position.
 20. Thereversion control device of claim 19 further comprising a flapper stoppin to limit the pivoting action of the flapper.
 21. The reversioncontrol device of claim 19, wherein the hinge tube is an integral partof the flapper.
 22. The reversion control device of claim 19, whereinthe flapper includes a face and wherein the hinge tube is located on theface such that, when the flapper is mounted within the housing, the faceof the flapper is at an angle Θ (theta) between about 20 to about 60degrees.
 23. The reversion control device of claim 22, wherein the angleΘ (theta) is about 35 degrees.
 24. The reversion control device of claim1, wherein the proximal end includes a circumference that issubstantially circular.
 25. The reversion control device of claim 1,wherein the proximal end includes a circumference that is partiallycircular, with a flat portion.
 26. The reversion control device of claim1, wherein the housing has a length L of about 8 inches.
 27. Thereversion control device of claim 1, wherein the housing has a diameterof about 3 inches.
 28. The reversion control device of claim 1, whereinthe housing includes an expansion chamber to house the first reversioncone, the stationary vane and the flapper.
 29. The reversion controldevice of claim 28, wherein the transition from the expansion chamber tothe proximal end is a substantially straight linear transition.
 30. Thereversion control device of claim 28, wherein the transition from theexpansion chamber to the proximal end is a substantially curvedtransition.
 31. The reversion control device of claim 28, wherein theratio between a first diameter d₁ of the distal end to a second diameterd₂ of the expansion chamber is between about 1.5 to about 3 times. 32.The reversion control device of claim 1 further comprising an oxygensensor for monitoring oxygen content.
 33. The reversion control deviceof claim 32 wherein the housing further comprises a threaded hole formounting the oxygen sensor.
 34. A reversion control device comprising: ahousing with a proximal end, a distal end and an expansion chamber, afirst reversion cone housed within the expansion chamber near the distalend; a stationary vane housed within the expansion chamber near thedistal end; and a flapper housed within the expansion chamber near theproximal end.
 35. The reversion control device of claim 34, wherein thestationary vane is housed within the first reversion cone.
 36. Thereversion control device of claim 34 further comprising a secondreversion cone housed near the proximal end.
 37. An exhaust system forcontrolling water reversion comprising: a reversion control devicecomprising a housing with a proximal end, a distal end, and an expansionchamber between the proximal end and the distal end; a first reversioncone housed within the expansion chamber; a stationary vane housedwithin the expansion chamber; and a flapper housed within the expansionchamber; at least one exhaust mixture hose support attached to thereversion control device on the housing; and an exhaust mixture hosecoupled to at least one exhaust mixture hose support, the exhaustmixture hose surrounding the reversion control device.
 38. The exhaustsystem of claim 37, wherein the reversion control device furthercomprises a second reversion cone housed within the expansion chamber.39. An exhaust manifold elbow comprising: a reversion control devicehoused within the exhaust manifold elbow, the reversion control devicecomprising a proximal end, a distal end, a first reversion cone housednear the distal end, a stationary vane housed near the distal end, and aflapper housed near the proximal end.
 40. The exhaust manifold elbow ofclaim 39, wherein the reversion control device further comprises adiffuser edge housed near the distal end.
 41. The exhaust manifoldelbow-of claim 39, wherein the reversion control device furthercomprises a second reversion cone housed near the proximal end.
 42. Anexhaust manifold elbow comprising: a reversion control device housedwithin the exhaust manifold elbow, the reversion control devicecomprising a proximal end, a distal end, an expansion chamber betweenthe distal end and the proximal end, a first reversion cone housedwithin the expansion chamber, a stationary vane housed within theexpansion chamber, a flapper housed within the expansion chamber, and asecond reversion cone housed in the proximal direction of the exhaustmanifold elbow.